﻿//-----------------------------------------------------------------------
// <copyright file="ITransformState.cs" company="Nathan Miller">
// Copyright (c) Nathan Miller.
//
// Permission is hereby granted, free of charge, to any person obtaining
// a copy of this software and associated documentation files (the
// "Software"), to deal in the Software without restriction, including
// without limitation the rights to use, copy, modify, merge, publish,
// distribute, sublicense, and/or sell copies of the Software, and to
// permit persons to whom the Software is furnished to do so, subject to
// the following conditions:
// 
// The above copyright notice and this permission notice shall be
// included in all copies or substantial portions of the Software.
// 
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
// EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
// NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
// LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
// OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
// WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
// </copyright>
//-----------------------------------------------------------------------
namespace TileTool.Editor.Transform
{
    using System;
    using TileTool.Common.Math;
    using TileTool.Editor.Grid;
    using TileTool.Scene.Entity;

    /// <summary>
    /// Interface for a transform state which drives how objects are manipulated.
    /// </summary>
    public interface ITransformState
    {
        #region Events

        /// <summary>
        /// Event triggered when the state changes.
        /// </summary>
        event Action<ITransformState> Changed;

        #endregion

        #region Properties

        /// <summary>
        /// Grid we are using. Should always be non-null.
        /// </summary>
        IGrid Grid
        {
            get;
        }

        /// <summary>
        /// Gets the snap state we are using. Should always be non-null.
        /// </summary>
        ISnapState SnapState
        {
            get;
        }

        /// <summary>
        /// Gets the current coordinate system for the transform state.
        /// </summary>
        CoordinateSystem System
        {
            get;
        }

        /// <summary>
        /// Gets the currently picked object which we will use as our coordinate system.
        /// 
        /// CoordinateSystem must be CoordinateSystem.Pick for this to be valid.
        /// </summary>
        IEntity PickObject
        {
            get;
        }

        /// <summary>
        /// Gets the matrix for our coordinate system.
        /// 
        /// For a single selection, orientation will based on System and
        /// the position will be the position will be the position of the object.
        /// 
        /// For multi-selection, orientation will always be Identity and
        /// the position will be the lower left corner of the bounding rect
        /// of all selected objects.
        /// </summary>
        Matrix2D Matrix
        {
            get;
        }

        #endregion
    }
}
